Succession, the development of biological communities through time, is a central theme of ecology. It is becoming increasingly clear that soil organisms play a large role in succession of plant communities, yet the role of soil microbes in this context is still very poorly understood, particularly with respect to arbuscular mycorrhizal fungi (AMF). AMF, common root associates with the majority of plants, are pervasive components of soils. They significantly influence plant growth and soil processes. How will AMF abundance and communities change through time, and how can these changes influence plants and soils? These questions will be addressed using the landscape created by a free-flowing river in Montana, providing a sequence of site ages (0 to 70 years), a natural laboratory. By measuring AMF abundance, species composition, and function in soils of these different ages, a better understanding of their role in succession can be derived. The main focus is the function of soil aggregation; this action of AMF contributes to the stabilization of soils, a crucial property related to erosion resistance.
Rivers are organizing centers of diversity in a landscape, and riverine soils are among the most fertile, yet fragile on Earth. These soils, which are subject to increased exposure to pressures from humans, represent important nutrient and waste buffers between terrestrial, groundwater and river systems. Therefore, in addition to fundamental contributions to understanding ecological succession, data from this project will also serve to inform restoration and conservation efforts related to rivers.
